Study: Agent Orange may still affect Vietnamese

Agent Orange was dropped on Vietnam by the U.S. military more than 30 years ago

DALLAS, Texas (CNN) -- More than 30 years after Agent Orange was last dropped on Vietnam by the U.S. military, it continues to contaminate people there, according to the results of a study released Monday.

The study, published in the Journal of Occupational and Environmental Medicine, found 19 of 20 blood samples from people living in Bien Hoa City, near an air base used by the U.S. military for Agent Orange spraying missions during the war, contained high levels of dioxin, an ingredient in Agent Orange.

In some cases, levels were up to 135 times as high as those found in people in Hanoi, where Agent Orange wasn't sprayed, the study found.

Dioxin has been linked to cancer and reproductive developmental effects in humans. During the war, the U.S. military used Agent Orange to defoliate jungle, dropping approximately 18 million gallons over about 10 percent of southern Vietnam. More than 36 million people live in these areas today.

However, the lead author of the study, Dr. Arnold Schecter of the University of Texas School of Public Health in Dallas, said the research doesn't yet establish a link between the dioxin contamination and illness.

Some 7,500 gallons of Agent Orange were spilled at the U.S. base near Bien Hoa City more than 30 years ago, and soldiers and residents alike were soaked with it during the war. However, many of those people in the study found to be contaminated with dioxin were born or moved to the area long after the war.

This indicates that the contamination is ongoing, said Schecter. Tests on soil and lake sediment show they may be the source of the ongoing contamination, and it is possible that fish in contaminated rivers could also be a source, Schecter said.

The elevations were striking, he said. In blood taken from people living in Hanoi, where Agent Orange was not sprayed, a form of dioxin was typically present at 2 parts per trillion. But dioxin levels among Bien Hoa City residents were as high as 271 parts per trillion, more than 135 times as high, he said.

Bien Hoa's population is 400,000. It is 15 miles north of Ho Chi Minh City, formerly Saigon. Schecter said he did not know how many people might be at risk from the contamination.

"This means there are 'hot spots' in Vietnam of concern to the Vietnamese right now," he said. Negotiations between U.S. and Vietnamese government officials are ongoing concerning research, clean-up and humanitarian assistance regarding the contamination, he said.

"It's a bad actor," said Schecter about Agent Orange in Vietnam. "And this is the biggest dioxin contamination in the world."

The study might also have implications for the 3 million U.S. veterans who served in Vietnam, he said. Veterans who served in highly contaminated areas "are more likely to have been contaminated and therefore be at higher health risk," he said.

The study could also be relevant to U.S. residents who live near Superfund sites contaminated with dioxin. "This means we need to take a look at [them]," Schecter said.

In an editorial accompanying the study, Dr. Michael Gochfeld of the University of Medicine and Dentistry of New Jersey said that "although wishful thinkers might have assumed that the problem would go away over time, the data presented in this article indicate that for some populations, the exposure continues."